The objectives of the proposed project are: 1. To discover new inherited endocrine, neurological, and immunological mutations to the mouse; 2. To maintain as breeding pairs and preserve as frozen embryos a number of established mouse mutations and chromosomal aberrations; 3. To develop genetically suitable stocks of new and established mouse mutations for use as animal models in biomedical research; and 4. To make the mutants available to interested investigators in the scientific community.